Python类继承，缺少属性

Question

我学习Python和Python的脚本在我的学习道路运行远程SSH命令 脚本本身运行正常，但它打破当我要进行实验类继承功能。

原创剧本pyssh.py：

#!/usr/bin/env python 
import sys 
import socket 
import paramiko 
#================================= 
# Class: PySSH 
#================================= 
class PySSH: 


    def __init__ (self): 
     self.ssh = None 
     self.transport = None 

    def disconnect (self): 
     if self.transport is not None: 
      self.transport.close() 
     if self.ssh is not None: 
      self.ssh.close() 

    def connect(self,hostname,username,password,port=22): 
     self.hostname = hostname 
     self.username = username 
     self.password = password 

     self.ssh = paramiko.SSHClient() 
     #Don't use host key auto add policy for production servers 
     self.ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy()) 
     self.ssh.load_system_host_keys() 
     try: 
      self.ssh.connect(hostname,port,username,password) 
      self.transport=self.ssh.get_transport() 
     except (socket.error,paramiko.AuthenticationException) as message: 
      print "ERROR: SSH connection to "+self.hostname+" failed: " +str(message) 
      sys.exit(1) 
     return self.transport is not None 

    def runcmd(self,cmd,sudoenabled=False): 
     if sudoenabled: 
      fullcmd="echo " + self.password + " | sudo -S -p '' " + cmd 
     else: 
      fullcmd=cmd 
     if self.transport is None: 
      return "ERROR: connection was not established" 
     session=self.transport.open_session() 
     session.set_combine_stderr(True) 
     #print "fullcmd ==== "+fullcmd 
     if sudoenabled: 
      session.get_pty() 
     session.exec_command(fullcmd) 
     stdout = session.makefile('rb', -1) 
     #print stdout.read() 
     output=stdout.read() 
     session.close() 
     return output 

#=========================================== 
# MAIN 
#===========================================   
if __name__ == '__main__': 
    hostname = 'server1' 
    username = 'admin' 
    password = 'Password123' 
    ssh = PySSH() 
    ssh.connect(hostname,username,password) 
    output=ssh.runcmd('date') 
    print output 
    output=ssh.runcmd('service sshd status',True) 
    print output 
    ssh.disconnect() 

现在我想用拧干的新脚本pyssh2.sh

#!/usr/bin/env python 
from pyssh import PySSH 
class PySSHT(PySSH): 
    def connect(self,hostname): 
     self.ssh = PySSH() 
     self.username = 'admin' 
     self.password = 'Password1' 
     self.ssh.connect(hostname,self.username,self.password) 

host = 'server1' 
ssh = PySSHT() 
ssh.connect(host) 
output=ssh.runcmd('date') 
print output 
output=ssh.runcmd('service sshd status',True) 
print output 
ssh.disconnect() 

它给了这个错误，测试类的继承，看来自我的价值。在ssh.connect（）中分配的传输在runcmd（）中丢失。有没有简单的类继承规则我缺少？

[[email protected] ~]# ./pyssh2.py 
ERROR: connection was not established 
ERROR: connection was not established 
Traceback (most recent call last): 
    File "./pyssh2.py", line 17, in <module> 
    ssh.disconnect() 
    File "/root/pyssh.py", line 19, in disconnect 
    self.ssh.close() 
AttributeError: PySSH instance has no attribute 'close 

Answer 1

看起来你的问题是在这里：

class PySSHT(PySSH): 
    def connect(self,hostname): 
     self.ssh = PySSH() # <=== problem here? 
     self.username = 'admin' 
     self.password = 'Password1' 
     self.ssh.connect(hostname,self.username,self.password) 

在第一个代码块中，第二块（上面）设置self.ssh到paramiko.SSHClient（） 您设置到PySSH

我认为paramiko.SSHClient有.close方法。 PySSH没有。

你不应该设置self.ssh到PySSH我不认为。 更好的方法是这样的：

class PySSHT(PySSH): 
    def connect(self, hostname): 
     PySSH.connect(self, hostname = hostname, username = 'admin', password = 'Password1') 
     return 

你也应该对旧式VS新式类在Python阅读起来。 PySSH或许应该得到声明：

class PySSH(object):